Process and system for anode overpressure remedial action in a fuel cell system

Abstract

A process for anode overpressure remedial action in a fuel cell system is provided. The process includes monitoring a pressure of hydrogen gas at an anode of a fuel cell stack of the fuel cell system, diagnosing a mechanically stuck open injector based upon the monitored pressure, and based upon diagnosing the mechanically stuck open injector, closing a valve within a hydrogen storage system to prevent flow of the hydrogen gas from a hydrogen storage tank into a gas line connecting the hydrogen storage tank to the mechanically stuck open injector and maintaining operation of the fuel cell stack to deplete the hydrogen gas at the anode.

What is claimed is: 
     
         1 . A process for anode overpressure remedial action in a fuel cell system, comprising monitoring a pressure of hydrogen gas at an anode of a fuel cell stack of the fuel cell system;
 diagnosing a mechanically stuck open injector based upon the monitored pressure;   based upon diagnosing the mechanically stuck open injector:
 closing a valve within a hydrogen storage system to prevent flow of the hydrogen gas from a hydrogen storage tank into a gas line connecting the hydrogen storage tank to the mechanically stuck open injector; and 
 maintaining operation of the fuel cell stack to deplete the hydrogen gas at the anode. 
   
     
     
         2 . The process of  claim 1 , further comprising shutting down the fuel cell stack once the monitored pressure remains below a threshold pressure for a selected time period. 
     
     
         3 . The process of  claim 1 , wherein maintaining operation of the fuel cell stack is based upon preventing the pressure of the hydrogen gas at the anode from exceeding a fuel cell hardware pressure limit. 
     
     
         4 . The process of  claim 1 , further comprising closing a plurality of valves within the hydrogen storage system to prevent flow of the hydrogen gas from a plurality of hydrogen storage tanks into the gas line connecting the hydrogen storage tank to the mechanically stuck open injector. 
     
     
         5 . The process of  claim 1 , wherein the mechanically stuck open injector comprises a first injector; and
 further comprising closing a second injector.   
     
     
         6 . The process of  claim 1 , further comprising, based upon diagnosing the mechanically stuck open injector, opening an anode bleed valve to permit the hydrogen gas to exit an anode gas line of the fuel cell stack. 
     
     
         7 . The process of  claim 6 , further comprising, based upon diagnosing the mechanically stuck open injector, closing an anode drain valve operable to release by-product water from the fuel cell system. 
     
     
         8 . The process of  claim 6 , further comprising, based upon diagnosing the mechanically stuck open injector:
 commanding increased pressure from an air compressor supplying pressurized air to the fuel cell stack; and   opening a cathode bypass valve.   
     
     
         9 . The process of  claim 6 , further comprising, based upon diagnosing the mechanically stuck open injector, partially closing a cathode backpressure air valve to increase a cathode pressure of the fuel cell stack and control a difference in pressure between the pressure of the hydrogen gas at the anode and the cathode pressure. 
     
     
         10 . The process of  claim 6 , further comprising, based upon diagnosing the mechanically stuck open injector:
 monitoring a decrease in a difference in pressure between the pressure of the hydrogen gas at the anode and the cathode pressure of the fuel cell stack; and   in response to the monitored decrease, closing the anode bleed valve.   
     
     
         11 . The process of  claim 6 , further comprising, based upon diagnosing the mechanically stuck open injector:
 opening an anode drain valve operable to release by-product water from the fuel cell system and releasing the hydrogen gas through the anode drain valve;   determining a hydrogen gas component within a fuel cell exhaust line; and   closing the anode drain valve if the hydrogen gas component exceeds a threshold emissions value.   
     
     
         12 . A process for anode overpressure remedial action in a fuel cell system, comprising within a computerized fuel cell system control module, operating programming to:
 monitor a pressure of hydrogen gas at an anode of a fuel cell stack of the fuel cell system;   diagnose a mechanically stuck open injector based upon the monitored pressure;   based upon diagnosing the mechanically stuck open injector:
 closing a valve within a hydrogen storage system to prevent flow of the hydrogen gas from a hydrogen storage tank into a gas line connecting the hydrogen storage tank to the mechanically stuck open injector; 
 maintaining operation of the fuel cell stack to deplete the hydrogen gas at the anode; 
 opening an anode bleed valve to permit the hydrogen gas to exit an anode side of the fuel cell stack; 
 commanding increased pressure from an air compressor supplying pressurized air to the fuel cell stack; 
 opening a cathode bypass valve; 
 partially closing a cathode backpressure air valve to increase a cathode pressure of the fuel cell stack and control a difference in pressure between the pressure of the hydrogen gas at the anode and the cathode pressure; 
 monitoring a decrease in a difference in pressure between the pressure of the hydrogen gas at the anode and the cathode pressure of the fuel cell stack; and 
 in response to the monitored decrease, closing the anode bleed valve. 
   
     
     
         13 . The process of  claim 12 , further comprising shutting down the fuel cell stack once the monitored pressure remains below a threshold pressure for a selected time period. 
     
     
         14 . The process of  claim 12 , wherein maintaining operation of the fuel cell stack is based upon preventing the pressure of the hydrogen gas at the anode from exceeding a fuel cell hardware pressure limit. 
     
     
         15 . The process of  claim 12 , further comprising closing a plurality of valves within the hydrogen storage system to prevent flow of the hydrogen gas from a plurality of hydrogen storage tanks into the gas line connecting the hydrogen storage tank to the mechanically stuck open injector. 
     
     
         16 . A system for anode overpressure remedial action in a fuel cell system, comprising a fuel cell stack of the fuel cell system comprising an anode;
 a pressure sensor operable to monitor a pressure of hydrogen gas at the anode;   an injector operable to selectively provide a flow of the hydrogen gas to the anode;   a hydrogen storage tank;   a gas line connecting the hydrogen storage tank to the injector;   a valve operable to selectively seal off the hydrogen storage tank;   a computerized fuel cell system control module programmed to:
 monitor data from the pressure sensor; 
 diagnose a mechanically stuck open injector based upon the monitored data; 
 based upon diagnosing the mechanically stuck open injector:
 closing the valve operable to selectively seal off the hydrogen storage tank; and 
 maintaining operation of the fuel cell stack to deplete the hydrogen gas at the anode. 
 
   
     
     
         17 . The system of  claim 16 , further comprising an anode bleed valve operable to selectively permit the hydrogen gas to flow from a gas line connecting the injector to the anode to a gas line connected to a cathode of the fuel cell stack; and
 wherein the computerized fuel cell system control module is further programmed to, based upon diagnosing the mechanically stuck open injector, open the anode bleed valve.   
     
     
         18 . The system of  claim 17 , further comprising:
 an air compressor supplying compressed air to the gas line connected to the cathode of the fuel cell stack; and   a cathode bypass valve selectively permitting air within the gas line connected to the cathode of the fuel cell stack to bypass the cathode of the fuel cell stack; and   wherein the computerized fuel cell system control module is further programmed to, based upon diagnosing the mechanically stuck open injector, ramp up the air compressor to increase an air pressure within the gas line connected to the cathode of the fuel cell stack and open the cathode bypass valve.   
     
     
         19 . The system of  claim 18 , wherein the computerized fuel cell system control module is further programmed to:
 subsequent to diagnosing the mechanically stuck open injector, diagnose a drop in the pressure of the hydrogen gas at the anode based upon the monitored data; and   based upon the diagnosed drop in the pressure of the hydrogen gas at the anode, close the anode bleed valve.   
     
     
         20 . The system of  claim 16 , further comprising an anode drain valve operable to release by-product water from the fuel cell system; and
 wherein the computerized fuel cell system control module is further programmed to release the hydrogen gas through the anode drain valve.